The present invention relates to a self-locking belt-like device for bundling to a unitary arrangement a plurality of linear objects such as cables and wires or for closing the opening of bag-type containers. More particularly, the invention relates to an improved bundling belt device having an improved bundling performance.
In a variety of electric apparatus, use is made of a number of conductor wires and/or cables, and in the manufacture of such apparatus, it is widely practiced to utilize belt- or strap-type devices for orderly bundling the number of wires and/or cables group by group in order to facilitate the operation for assembling the apparatus and avoid the occurrence of any accident or error in the operation.
Bundling devices of the mentioned type are broadly classified into such ones as made of a metal and others made of a synthetic resin. With metal-made devices, while they can exhibit a high bundling strength, they are comparatively costly to manufacture and relatively difficult to handle, so that they are limited in their possible utility only to for example such cases where linear objects to be bundled are of a relatively great size and/or weight. With resin-made devices, then, they are possessed of desirable characteristics with respect to the electric insulation, flexibility, easiness for handling and so forth, and yet they can be produced in mass by molding, at a low cost, so that in recent years they have grown to be used in increasingly great numbers.
The self-locking bundling belt device according to the present invention is of the type made of a synthetic resin. Known devices of this type may be represented by the one disclosed in the U.S. Pat. No. 3,967,345 to Sumimoto. In this patent, the resin-made binding strap comprises a cylindrical head having a tongue rockably provided in the opening thereof and a strap continuously extended from a side wall portion of the head and formed on the lower side face thereof with teeth. The arrangement is such that in use of the device, the strap applied to bundle objects is inserted into the opening of the head, when the tongue in the head is meshed with the teeth on the strap as in ratchet devices. With this known binding device, the engagement between the strap and the head is effected as solely relied on a mutual meshing of the tongue and a portion of the teeth, and according to experiences with the device, there have been some difficulties encountered: It easily tends to occur that although objects to be bundled have in fact been not sufficiently bundled, the operator under the bundling operation is caused to in error assume as if a complete bundling had already been made. Further, in order to effect a tight bundling of objects, the operator is required to exert a strong force of pulling the strap passed, with its leading end portion, through the opening in the head. Particularly, it has become increasingly demanded of late that a single bundling belt device can bundle a greater number of linear objects of a same size as before or a same number of objects having a greater size than before, and in order to cope with such demands, it has grown to be required to make the device greater in size. Then, as the device is larger, less rockable becomes the tongue formed in the head, and the tongue then exerting a greater reaction force against the strap as the latter is inserted into and passed through the opening in the head, the bundling operation is inconveniently affected, resulting in a lowering of the operation efficiency. A further difficulty with the known device under reference resides in that the free end or leading end of the strap in a fastened condition of the device is projected in a perpendicular direction relative to the axes of bundled linear objects, so that not only the device presents an appearance reminding its user or an observer of a danger or an otherwise uneasy impression but also the projected free end of the strap in fact forms an obstacle to the bundling and/or transportation operations or even gives rise to a danger to the bundling operator.